Fragrances have long been used to provide a pleasing scent to tumble dried fabrics as well as to mask or reduce malodors of fabric conditioning agents used in tumble dryer articles.
The harsh conditions of manufacturing such articles as well as dryer times and temperatures are deleterious to volatile perfume notes. Much of the perfume added to the fabric conditioning compositions is lost prior to removing dried fabrics from the tumble dryer.
Many techniques have been tried to entrap the volatile fragrance oil to enhance its deposition on dried fabrics and to extend its fragrance upon use or wear. Such prior art techniques involve encapsulating perfume oils in cyclodextrin complex carriers as illustrated in EP 392,607, EP 392,606 and WO 9117300. Although the use of cyclodextrin complexes is technically sound, the materials are expensive and add an undesirable upcharge to manufacturing cost.
Water insoluble polymeric carriers have been used to encapsulate perfumes used in fabric conditioners as described in U.S. Pat. Nos. 4,076,633; EP 397,246; and EP 397,245. Such carriers are impervious to water and release perfume upon heat activation. Extended release of the perfume through use or wear is therefore generally not achieved when such carriers are used.
Perfumes have also been adsorbed onto various materials such as silica and clay to deliver perfume in detergents and fabric softeners as illustrated in U.S. Pat. No. 4,954,285 issued to Wierenga et al. and U.S. Pat. No. 4,536,315. In general, the fragrance oil is not sufficiently protected so that it is frequently lost or destabilized during processing.
Water soluble polymers have been used to encapsulate fragrance oils as described in U.S. Pat. Nos. 4,276,312; 3,821,436 and EP 480 520. Such capsules have proved useful in releasing perfume in deodorant applications, however, have not been commercially successful in extended release of perfume from fabrics dried in tumble dryers.
It is thus an object of the present invention to provide a tumble dryer article containing encapsulated perfume capsules which will prevent the loss of the majority of the fragrance oil during processing, storage and use of the fabric conditioning articles and at the same time will release the majority of the fragrance onto dried fabrics during their use or wear.
Another object of the invention is to provide an extended release of perfume onto dried fabrics in response to an aqueous trigger.